Numerical Investigation of Mixing Performance for a Vertical Turbulence Mixer

Abstract

Abstract In this work, discrete element method (DEM) was employed to analyze mixing performance of a vertical turbulence mixer. The lacey mixing index was used to quantify mixing degree while a mixing rate was proposed to evaluate mixing speed. Several typical structural and operating parameters affecting mixing performance was investigated including initial loading pattern, rotational speed of stirring shaft and filling level. Results showed that mixing of top-bottom loading is faster than that of side-side loading. Comparing with another factor, stirring shaft rotating speed and filling level had more significant influence. A nearly linear growth and an almost linear decline relationships with mixing rate was found for the rotary speed and filling level respectively. A higher rotational speed or a lower filling level could help form a more intensive granular turbulent flow, resulting in faster mixing. Application of this work provides instruction to optimization of geometry and parameters of mixing systems to improve the quality of the mixing process.